The battery slides in the bottom. a little tight but will fit. I cut out the inside to fit a 1500mah 3s lipo. should be a white battery door and put oone end through and slide it back then snap the door back on. I will try to post some pics of my mods and part numbers that turns it into a beast. havnt flown it in a while but looking at rebuilding it soon. Good luck email me at [email protected] if you need and info